Multiple separation of self-running drops by pinching a three-phase contact line

We produced multiple minute self-running drops from an original drop without external input power by pinching a three-phase contact line. By branching into surface energy barriers, the drop is forced to separate while translating on a flat surface. A symmetry in the drop front wetted perimeter conduces to equal division of the drop. Our experiments suggest that at least seven divisions (128 drops) can be conducted sequentially to give equal final volumes of approximately 4 nl. A division of carrier liquid volume by 1/2(7) is expected to enable multiple analysis on many separate stations. This is the only drop separation method at present that does not require external power input.